This invention relates to a means for holding a septum in a septum closed tubular percutaneous device and to special septum configurations therefor.
In co-pending application Ser. No. 261,709 filed May 8, 1981, as a Continuation of Ser. No. 138,579 filed Apr. 8, 1980, there is disclosed an implantable generally T-shaped percutaneous structure in which the stem of the T is constructed and arranged to cooperate with a needle structure that penetrates a septum seal means at the junction of the stem of the T with the balance of the T structure. The arms of the T may be connected to a blood vessel directly or via intermediate flexible tubes of a material such as expanded polytetrafluorethylene. The T-stem protrudes through the skin layer, thereby providing access to the circulatory system through the septum. By reason of the structure of the invention, the interior stemmed portion of the T can be rinsed clean and sterilized between each use without elaborate procedures, thus minimizing the likelihood of infection as a result of access to the circulatory system.
In co-pending application, Ser. No. 209,058, filed Nov. 21, 1980, there are described a number of improvements and accessories for such a tubular T-shaped blood access device. These improvements include a pre-slit septum having a circumferential side groove which carries an elastomeric O-ring for extended sealing life, an improved cooperating needle carrier structure, a septum assembly insertion tool and a variety of additional structure and accessories.
In co-pending application, Ser. No. 314,569, filed Oct. 26, 1981, as a continuation-in-part of application Ser. No. 261,709, there are described similar tubular, septum closed, percutaneous devices for other applications, such as peritoneal dialysis and chemotherapy.
The disclosures of applications Ser. Nos. 261,709, 209,058 and 314,569 are incorporated herein by reference.
The means for retaining the septum in the stem of the percutaneous devices of the aforementioned applications, Ser. Nos. 261,709, 209,058 and 314,569, is a pressure plate defining a pair of needle holes therethrough which is in turn held in place by a retaining ring fitted into a groove in the T-stem. This structure can be very cumbersome during removal and replacement of the septum. Septum replacement in such a structure entails sequential removal of the retaining ring, the pressure plate and the septum followed by replacement of new piece parts. While steps may be taken to reduce blood flow during replacement, substantial blood loss can occur even when a specialized septum loading tool as described in application Ser. No. 209,058 is used to simultaneously insert the new septum, pressure plate and retaining ring.